. Bulletin. Science. DRY WEATHER FLOW TOXICITY: SANTA MONICA BAY 39 >18 CO c o â â¢"« X o. Toxic units = 100/EC50 (4) Toxic Nontoxic Ashland ] Feb. 1991 Ballona Pico-Kenter â 1992 Sepulveda Dec. 1992-Jan. 1993 Fig. 3. Variability in sea urchin (Strongylocentrotus purpuratus) fertilization test results with time and storm drain location. Results of concurrent reference toxicant (copper) tests for each set of samples are shown in parentheses. Even greater temporal variation was present between Ballona Creek samples. Three samples taken within the span of approximately one mont
. Bulletin. Science. DRY WEATHER FLOW TOXICITY: SANTA MONICA BAY 39 >18 CO c o â â¢"« X o. Toxic units = 100/EC50 (4) Toxic Nontoxic Ashland ] Feb. 1991 Ballona Pico-Kenter â 1992 Sepulveda Dec. 1992-Jan. 1993 Fig. 3. Variability in sea urchin (Strongylocentrotus purpuratus) fertilization test results with time and storm drain location. Results of concurrent reference toxicant (copper) tests for each set of samples are shown in parentheses. Even greater temporal variation was present between Ballona Creek samples. Three samples taken within the span of approximately one month ranged from strongly toxic (7 TU) to nontoxic (<2 TU). No long-term trends were evident at Ballona Creek; toxicity of a sample collected the previous year (February 1991) fell within the range measured in 1992-93 (Fig. 3). Results of reference toxicant (copper chloride) tests varied by about a factor of two, indicating that variations in fertilization test sensitivity, though present, were within acceptable limits. Variations in reference toxicant response did not correspond to the temporal or spatial variability in dry weather flow toxicity (Fig. 3). General Constituents of Dry Weather Flow Water quality measurements indicate variations in effluent composition be- tween sites despite similar land use distributions (Table 2). Samples from Ashland usually had the poorest water quality. For example, Ashland had higher levels of suspended solids, chemical oxygen demand, dissolved organic carbon, turbidity, and ammonia than the other sites. Dissolved oxygen concentration was also low at Ashland and a sulfide odor was usually present. The ocean discharge pipe for. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Southern California Academy of Sciences. Los Angeles, Calif. : The Academy
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